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Now that Linux is a major platform in the corporate data center, the need for management tools is clear. One such product is SUSE Manager, which, despite its name, manages more than just SUSE's Linux distribution.
Linux administrators face a challenge: deploying patches in an orderly manner. Enterprise Linux distributions such as Red Hat Enterprise Linux (RHEL) and SUSE Linux Enterprise Server (SLES) fetch patches directly from the vendor-provided servers over the Internet. In corporate environments, however, you need to test and stage patches before rolling them out to the data center servers. And if things go wrong, it must be possible to roll back changes.
Two of the most important features of SUSE Manager are patch management and staging. In an enterprise data center, the servers contact SUSE Manager, which prepares the patches in channels. This organization enables administrators to distinguish between different groups of servers, so specific patches can go to certain servers only.
Within a channel, you can also define different phases in the staging process. This allows an administrator to define testing, preproduction and production stages for specific environments. Freezing patches at a specific moment is easy, since the software allows the administrator to create a snapshot after which no updates are applied.
SUSE Manager uses a pull mechanism as well as a push mechanism to access updates and patches. The pull mechanism instructs servers to download information at a specific point in time, while the push mechanism instructs the SUSE Manager server to contact an agent that runs on subscribed nodes to push patches to them.
Patch deployment is just one aspect of Linux server management in corporate environments. Other areas such as server configuration files need administration. SUSE Manager enables remote access, so support staff can connect to a managed server regardless of location. As these functions are often applied through other configuration management systems such as Puppet, this part of the tool is less frequently purchased.
SUSE Manager dons a Red Hat
There are two different approaches to patch Red Hat servers through SUSE Manager. The official method lets SUSE take over the update management of Red Hat systems, replacing the Red Hat logo in the software packages with a SUSE logo and thus transferring the Red Hat software into the SLES Expanded Support distribution. This resembles what noncommercial Linux distro CentOS has been doing with Red Hat software for years, which is perfectly legal, as the source code of all Red Hat software components is freely available.
Changes in Linux systems management
SUSE Manager began as a downstream version of Spacewalk, an open source Linux systems management project that Red Hat founded. Red Hat used Spacewalk to develop Red Hat Satellite, which is its counterpart of SUSE Manager. Red Hat Satellite 6 and following versions, however, are based on a completely different approach. This has taken away a lot of development effort from the Spacewalk project, which calls into question the project's ongoing value for SUSE Manager. While SUSE states that this isn't going to be a problem at all, SLES users will have to wait to see if the company is capable of developing the complex SUSE Manager all by itself.
Some Linux IT shops don't like changing their Red Hat installations into the SLES Expanded Support distribution. For those companies, an alternative, yet not officially supported solution, has the Red Hat repositories synchronize to the SUSE Manager server. This allows the SUSE Manager server to put the Red Hat RPMs into SUSE channels and distribute them to subscribed Red Hat servers.
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